S. mansoni hypoxanthine-guanine phosphoribosyltransferase (HGPRTase) was identified as one of the pivotal enzymes in the purine salvage by the organism. One of our research goals is to verify the N-terminus of the HGPRTase and use the sequence for design of a vector for synthesis of the enzyme in bacteria. Conventional sequencing indicated that the N-terminus may be blocked, necessitating the use of alternate approaches, such as mass spectrometry.